Monocytes/macrophages constitute the first line of defence for external intrusion or infection. Circulatory monocytes represent about 10% of leukocytes in human blood and resident macrophages are distributed in a variety of tissues and organs to maintain body homeostasis. But relatively little is known about the consequences of chronic viral infections on monocytes. Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infections are the most important causes of chronic liver diseases, which may develop to serious and fatal liver pathology, including liver cirrhosis and hepatocellular carcinoma. Whether HBV and HCV infections are cleared or persist is determined by host immune responses. Viral replication takes place inside hepatocytes as soon as infection begins. The secretion of infectious virions or virus proteins can persist for decades at high rates. Chronic infections with HBV and HCV are the result of ineffective anti-viral immune response towards the virus. Interacting with virions or virus proteins, monocytes/macrophages play an important function in the disease process. The role of monocytes/macrophages in HBV and HCV infections or co-infections is discussed in this chapter.
Part of the book: Biology of Myelomonocytic Cells